This invention relates to a venting packer from which a vent pipe or tube extends so as to direct fluids away from piping where said fluids are unwanted. A typical situation is in a work area where flammable gas from piping apparatus is a dangerous hazard during repair or building and installation proceedures. For example, a section of pipe is often in need of repair or replacement, or additional apparatus is to be secured or welded into existant apparatus that has residual fluids therein. Such fluids are liquids and gases that are combustible and/or volatile, and such as to be ignited by flames or sparks generated during normal work proceedure. The dispositions of pipe sections and the surrounding environment will vary, and the work area will occur in the open or in confined spaces exposed to other potentially dangerous operations; and in such places as excavations and in under water installations. It is the isolation of combustible and/or explosive fluids with which this invention is primarily concerned, it being a general object to provide an extremely simple and practical venting packer that is reliable and readily adapted to a multitude of situations that require the assurance of safe working conditions, without failure.
Packers have been widely used in the oil field, and positioned within well casings and the like in order to perform various procedures. And, slips have been used to anchor the packers in position; also referred to as "anchor-packers". The principle of operation has been to expand both the slips and the packers, the former to anchor within the casings, and the latter to plug the casing or to shut off an annulus therein. A feature of packers is the ability to direct the flow of fluid therethrough, for whatever purpose may be required. However, combined anchor-packers of the prior art have been complicated by the particular task they perform, and are not reduced to simple practicality, it being an object of this invention to provide a venting anchor-packer that is reduced to its basic simple practicality and having an inherent mode of operation which is essentially fail-safe. That is, its effective operation can be relied upon without fail, there being no complexity subject to malfunction.
It is an object of this invention to provide a venting anchor-packer that is of plug form through which flow can occur while sealing off an extended annulus in a surrounding pipe, tube or casing. In the field, there are many situations where pipes are in need of repair or adaptation to or removal of other equipment. And, access to the area of repair is either upstream or downstream of a fluid source; in many cases a dangerous fluid. Accordingly, repair can be safely accomplished only by isolation from said dangerous fluid, and with this invention by plugging off the source of dangerous fluid and venting it away from the work area. In practice, a vent tube is attached to one body element of this plug device, to carry off the unwanted fluid, for example a flammable gas.
It is another object of this invention to provide a plug device that simultaneously anchors and packs by the direct application of mechanical forces from a single expansible slip member carried by the aforesaid one body member to which the vent tube is attached. A feature of this invention is the sectional body comprised of the aforesaid one body member in the form of a first cylinder member and a second piston member that carries expansible packer elements expanded by the aforesaid expansible slip member. A feature is the direct double function of the expansible slip member, that anchors and operates the packer elements.
It is still another object of this invention to provide a body and packer element combination that operates the slip element that retroactively operates the packer elements. There is no intervening mechanism, the slip element being shifted axially so as to expand radially. A feature of this invention is the telescoping first and second body members of this plug body that establishes an annular cylinder and through which the packed off fluid is vented into and through the vent tube. One of the body members is connected to a fluid pressure line for drawing the body members together, preferably to the movable piston member to transmit hydraulic liquid under suitable operating pressure.
It is an object of this invention to provide a fail-safe feature, in that the slips will not release under normal conditions even though there is a temporary loss of operating pressure in the hydraulic line. There is an unobvious feature provided by facing the slip wedge angle upwardly, while the opposed body wedge angle is faced downwardly to support the weight of the upstanding vent tube. In practice, radial expansion of the slip member is small and the wedge angles acute, so that weight of the vent tube applied to the frictional engagement of the slip and one body member prevents unintended release. Only by removal of vent tube weight and by deliberate lifting and/or jarring action can the slip member collapse for removal of this venting anchor-packer.